ISO/TC 173/SC 1/WG 11 - Wheelchair seating

This document specifies requirements for the selection, placement and fixation of flexible postural support devices within seating devices and systems and to chairs, including wheelchairs and bathroom equipment. Seating devices can be involved in one or more situations, including hoists, static seating, wheelchair seating, shower chairs, etc. The devices enable the seated person (the occupant) to be positioned to maximize their functional activities in a safe environment. These requirements are formulated to achieve a balance of posture maintenance and safety. This document covers flexible positioning supports (padded or otherwise) used for postural positioning and/or safety. It does not cover belts and harnesses used in transportation for restraint, postural support devices made from rigid materials such as metal, wood, or hard plastics, or postural support devices designed solely for use in sports-related seating.

This document specifies requirements for static, impact, and repetitive load strengths for postural support devices (PSDs) with associated attachment hardware intended for use with an undefined wheelchair seating system. It specifies the test methods for determining whether the minimum performance requirements have been met to release a product into use. It also specifies requirements for disclosure of the test results. Not all tests apply to all PSDs. This document is also applicable to other seating systems. The test methods can be used to verify the manufacturer’s claims that a product meets the requirements of this document. This document does not apply to PSDs that are designed to fail under certain static, dynamic, or repetitive loads. This document does not apply to the strength of PSDs under crash conditions in a motor vehicle. This document does not evaluate long-term useful life. NOTE 1 ISO 16840‑4 provides crash test methods and requirements for wheelchair seating systems when used as part of a wheelchair seat in a motor vehicle. NOTE 2 For user masses greater or less than those specified in this document, appropriate extrapolation of test apparatus dimensions, mounting point separation, forces, etc. can be carried out, and the test parameters noted in the test report. NOTE 3 Rigid surrogate test fixtures are utilized to provide a standardized test method, and consequently this document does not involve a test of a PSD on a particular wheelchair.

This document specifies a method for determining the dissipation characteristics of simulated sensible perspiration exposure on seat cushions of a wheelchair under test conditions that simulate body loading on support surfaces with flat and contoured profiles. The test method is applicable to a wide variety of seat cushion materials and constructions that are used across the world. The test method is intended to determine how the cushion handles a liquid load. It is not intended to determine how the cushion responds to a continuous release of liquid or vapour. This document also specifies apparatus to measure dissipation characteristics (of perspiration) of seat cushions and the approach to be employed in measuring these characteristics. This document is applicable to seat cushions for wheelchairs that include a cushion cover. NOTE The significance of the dissipation characteristics of the seat cushion can be greatly affected by the clothing worn, for example a moisture wicking cover might not help the skin condition of the patient sitting in a wet adult diaper.

This document specifies apparatus, test methods, and disclosure requirements for characterization of wheelchair seat cushion immersion and envelopment properties using indenters instrumented with pressure sensors. This document expands the characterization of products intended to manage tissue integrity (ISO 16840‑2) and provides a standardized indenter for other wheelchair seating tests. It does not provide information specific to cushion performance for a particular individual user, nor is it intended to characterize envelopment or immersion under higher loading conditions, nor to assess the weight capacity of a cushion. This document includes a method that is specific to 220 mm and 255 mm indenters. Dimensions are provided for a 380 mm indenter to allow for extension of the method to larger patient simulation.

This document specifies apparatus, test methods, and disclosure requirements for determination of lateral stability properties of wheelchair seat cushions by measuring the response from the cushion to a shift in the centre of mass of the load on the cushion. It provides a method of determining changes in a particular physical and mechanical property of the cushion. It does not provide information specific to cushion performance for a particular individual user. It does not provide information related to anterior-posterior stability, nor to stability contributions from cushion edges. NOTE 1 Test conditions simulate a symmetric anatomy. NOTE 2 Loads are intended to represent those seen under the pelvis of a 40th to 60th percentile wheelchair user. This document is applicable to cushions used in situations other than a wheelchair.

This document specifies requirements and test methods to assess the resistance to ignition by smouldering cigarette equivalent of integrated or non-integrated components of a wheelchair intended to protect tissue integrity and/or provide postural support. The electronic ignition source is also a simulation of other potential sources of environmental ignition hazards. The tests measure only the resistance to ignition of the items tested, and not the ignitability of the complete wheelchair. It gives an indication, but cannot guarantee, the ignition behaviour of the assembled devices of a complete wheelchair. This document does not apply to resistance to ignition of structural parts of a wheelchair. This document does not cover changes in resistance to ignition as a result of regular washing or use of the postural support devices. This document does not apply to the control of risks created by electrical and electronic components. This document allows for the separate testing of components of a wheelchair that are normally used in the horizontal plane (e.g. a seat cushion) from those normally used in the vertical plane (e.g. a back support). This document describes testing an assembly of the composite of materials as used in the component. The results of the tests in this document do not give any indication of the resistance to ignition of any of the separate individual materials of the test sample. NOTE The intent of this document is primarily to address components that interface with the human body, such as cushions for positioning, or whose described purpose is that of protecting skin tissue against pressure, shear, and maceration related damage, as well as textile, foam, and plastic-based postural support devices.

ISO 16840-2:2018 specifies apparatus, test methods and disclosure requirements for wheelchair seat cushions intended to maintain tissue integrity and prevent tissue trauma. Test conditions simulate a symmetric anatomy and posture and do not represent cushion performance for specific individual users. Loads are intended to represent those seen under the pelvis of a 50th percentile wheelchair user and are not intended to assess the weight capacity of the cushion or to characterize the cushion under bariatric loads. It is possible that not all test methods apply to existing and future cushion technologies. It does not include test methods or requirements for determining the fire resistance of cushions. ISO 16840-2:2018 can also be applicable to tissue integrity management devices used as other support systems, as well as to cushions used in situations other than a wheelchair.

ISO 16840-6:2015 specifies apparatus, test methods, and disclosure requirements for generating aging effects in a seat cushion that reproduce those seen in use. It also provides methods of determining changes in the physical and mechanical properties of seat cushions based on their age and use. ISO 16840-6:2015 provides a set of tests that simulate wear and tear, which can be useful to validate warranty claims and to provide information about product, life, and performance limitations associated with product use.

ISO/TR 16840-9:2015 has been produced to guide users in the performance of the tasks that are directly involved in the clinical use of interface pressure mapping (IPM) or are synergistic with its use in a comprehensive wheelchair seating evaluation. ISO/TR 16840-9:2015 does not cover other aspects of the clinical assessment process (e.g. taking a medical history), nor the prescription or treatment process which might arise from an assessment. These guidelines are not meant to be a substitute for clinical reasoning and judgement within the context of a complete assessment. ISO/TR 16840-9:2015 refers to the state of the art of IPM experiences in a seating scenario. Most of the principles covered can be extrapolated to whole body (in bed) or to foot assessments, for example.

ISO 16840-1:2006 applies to seating intended to provide postural support within a wheelchair. It specifies: a global coordinate system that permits the determination and recording of a person's posture while seated in a wheelchair; the standard terms and definitions for use in describing both the posture and the anthropometrics of a person seated in a wheelchair; the terms and definitions for describing the dimensions, location and orientation of seating support surfaces, which together comprise the body support system. ISO 16840-1:2006 does not specify any methods for use in measuring a person's seated posture, nor does it define terms for dynamic physiological movements (such as flexion or extension). ISO 16840-1:2006 might be applicable to seating other than that intended to be used within a wheelchair.

ISO 16840-10:2014 specifies requirements and test methods to assess the resistance to ignition by smouldering cigarette equivalent of non-integrated components of a wheelchair intended to protect tissue integrity. The test measures only the resistance to ignition by smouldering cigarette equivalent of the items tested and not the ignitability of the complete wheelchair. It gives an indication, but cannot guarantee, the ignition behaviour of the assembled non-integrated devices of a complete wheelchair. This part of ISO 16840 does not apply to resistance to ignition of structural parts of a wheelchair, nor does it cover postural support devices. This part of ISO 16840 does not cover changes in resistance to ignition as a result of regular washing or use. This part of ISO 16840 allows for the separate testing of removable non-integrated components of a wheelchair which are normally used in the horizontal plane (e.g. a seat cushion) from those normally used in the vertical plane (e.g. a back support). This part of ISO 16840 describes testing an assembly of the composite of materials as used in the removable non-integrated component. The results of this part of ISO 16840 do not give any indication of the resistance to ignition of any of the separate individual materials of the test sample. NOTE 1 The intent of this part of ISO 16840 is primarily to cover removable cushions whose described purpose is that of protecting skin tissue against pressure, shear, and maceration related damage. NOTE 2 The requirements of this part of ISO 16840 have been set at a basic minimal level and are less severe than mandatory requirements in some countries. Where practical, it is advisable that manufacturers use materials with superior resistance to ignition. The manufacturer is required to make the case as to why ISO 7176?16 could not be employed rather than this part of ISO 16840. NOTE 3 Requirements for the control of risks from sources of fire created by electrical and electronic components are included in ISO 7176?14

ISO 16840-3:2014 specifies test methods for the determination of static, impact, and repetitive load strengths as well as disclosure requirements for postural support devices (PSD) with associated attachment hardware intended for use with an undefined wheelchair.

ISO/TS 16840-11:2014 specifies a method for determining the dissipation characteristics of simulated perspiration exposure on wheelchair seat cushions. ISO/TS 16840-11:2014 is applicable to wheelchair seat cushions that include a cushion cover.

ISO 16840-2:2007 specifies apparatus, test methods and disclosure requirements for wheelchair seat cushions intended to maintain tissue integrity and prevent tissue trauma. It does not include test methods or requirements for determining the fire resistance of cushions and addresses neither the interface pressure distributing characteristics of seat cushions nor the heat and water vapour dissipation characteristics of seat cushions. ISO 16840-2:2007 can also be applicable to tissue integrity management devices used as other support systems, as well as to cushions used in situations other than a wheelchair.

ISO 16840-3:2006 specifies test methods for the determination of static, impact and repetitive load strengths as well as disclosure requirements for postural support devices (PSD) with associated attachment hardware intended for use with wheelchairs. ISO 16840-3:2006 does not test the transportability and the use of the PSD in a motor vehicle. NOTE At the present time there are no minimum or maximum strength requirements specified in the test procedures for testing for PSDs. In the future, minimum or maximum loads for testing might be specified for testing on a pass/fail basis. The maximum displacement, the maximum force achieved before failure and the type of failure that occurs is disclosed for comparison purposes.